Shape evolution in yttrium and niobium neutron-rich isotopes

The isotopic evolution of the ground-state nuclear shapes and the systematics of one-quasiproton configurations are studied in neutron-rich odd-A yttrium and niobium isotopes. We use a self-consistent Hartree-Fock-Bogoliubov formalism based on the Gogny energy density functional with two parametrizations, D1S and D1M. The equal-filling approximation is used to describe odd-A nuclei preserving both axial and time-reversal symmetries. Shape-transition signatures are identified in the $N=60$ isotopes in both the charge radii and spin parities of the ground states. These signatures are a common characteristic for nuclei in the whole mass region. The nuclear deformation and shape coexistence inherent to this mass region are shown to play a relevant role in the understanding of the spectroscopic features of the ground and low-lying one-quasiproton states. Finally, a global picture of the neutron-rich $A~100$ mass region from krypton up to molybdenum isotopes is illustrated with the systematics of the nuclear charge radii isotopic shifts.